Non-standard AS2 MDN response being sent to partner

A partner is sending an AS2 message and the webmethods response is a text/html “report” that includes in a cell way down in the HTML the ACTUAL MDN response that should be sent back to the partner. How is this being configured? See attached file - search for "Content-Type: multipart/signed; " and you will find the “embedded” resp[onse that is being expected but is instead wrapped up in what appears to be a webmethods report for internal logging